debentures, debenture stocks

[freelancer_06]

как так может быть
2 противоположных значения
и обеспеченный и необеспеченные?

в данном контексте как перевести?
To subscribe for, take, purchase or otherwise acquire, hold, sell, deal with and dispose of, place and underwrite shares, stocks, debentures, debenture stocks, bonds, obligations or securities issued or guaranteed by any other company constituted or carrying on business in any part of the world, ……..